The basic function of a power system is to continuously maintain adequate and reliable supply of electric power. However, performing this function is not always possible because various types of failures occur randomly beyond the control of power system engineers. Power system planners, designers, and operators are generally concerned with the reliability of the power system and then calculate approximately the realistic availability of their system. Recently, this concern has been accentuated by increasing competition among utility companies due primarily to de-regulation of the electrical power industry. Now, utility companies that once shared information across a common electrical grid are competing against themselves to provide distinguishable services in an effort to sustain existing customers and attract new customers.
Residential and business customers alike are increasingly dependent on power. From a simple switch to complex manufacturing equipment, power is required everyday. As a result of this new competition and the importance of power to customers, power systems are required to provide reliable, dependable, and more affordable power. Globally, power system engineers who maintain the operation and control of electrical power are challenged daily by consequences of electrical power being disrupted that translates directly to the quality, reliability and cost of electrical power. Utility companies have taken notice since the consequences of long-term unavailability and persistent interruption of electric power could directly translate to a loss of power customers.
The techniques first used in practical applications of power system design were developed to account for random failures. These techniques were generally deterministic in nature. Their primary weakness was a lack of consideration for the stochastic nature of system behavior, customer demands, and equipment failures.
In an effort to overcome power system limitations, power system equipment manufacturers developed devices, such as, power distribution protective relays and reclosers with control and operation schemes to achieve automated restoration of power systems. Existing restoration schemes, however, are rigid, requiring pre-defined configurations of power distribution system equipment and requiring pre-determined device settings.
Presently, there exist power distribution equipment incorporating restoration schemes that assist in bringing a power distribution system online in the event of a fault or loss of voltage. However, these restoration schemes place inflexible limits on the power distribution system. Such limits include pre-defined quantity, configuration and operation settings of equipment used in a restoration scheme.
From the foregoing, it is appreciated that there exists a need for a power system and method providing a robust restoration scheme that can be applied to power distribution systems, independent of power system equipment configuration or settings.